Recognition of High-Grade Invasiveness and Achievement of Gross Total Resection via an Endoscopic Endonasal Transsphenoidal Approach Promise Favorable Outcomes in Growth Hormone Pituitary Adenomas: 16 Years of Experience in a Single Institute

Background: Growth hormone (GH)-secreting pituitary tumors produce systemic comorbidities, thus achieving gross total resection (GTR) and biochemical remission are imperative. The aim of this study was to identify predictors affecting resection status and biochemical remission. Methods: : We retrospectively reviewed 54 GH adenoma patients receiving endoscopic endonasal transsphenoidal approach (EETSA). Medical records and magnetic resonance imaging were reviewed for tumor size, volume, resection status, invasion status, and Knosp and Hardy-Wilson grades. We also classified invasion status into high- and low-grade groups. Biochemical remission was defined as an insulin-like growth factor 1 value within sex- and age-adjusted reference or a random GH level < 1.0 ng/mL. Results: : The degrees of horizontal and vertical invasion based on preoperative Knosp and Hardy-Wilson grade were highly associated with intraoperative resection status (p=0.015, 0.014 and 0.017 respectively), but micro- or macroadenoma, tumor size and volume were not. We also found more significant differences between resection status and higher-grade invasion (p=0.006, 0.006 and 0.001, respectively). Knosp, Hardy-Wilson grades and resection status were significantly associated with biochemical remission (p=0.0007, 0.0428, 0.0006 and 0.0012, respectively). Although there was no difference between micro- or macroadenoma, tumor size and volume were statistically significant associated with outcomes (p=0.024, 0.0032, respectively). Similarly, more significant differences between biochemical remission and higher-grade invasion were found (p=0.00005, 0.009 and 0.00001, respectively). Conclusions: : EETSA remains the best treatment option for GH adenomas. Biochemical remission was highly associated with invasion status and the possibility of achieving GTR. Earlier diagnosis and more aggressive resection are key to favorable outcomes.